For the Empty Can Test, what indicates a positive result?

A positive result for the Empty Can Test is indicated by pain or weakness when resistance is applied during the test. This test is designed to assess the integrity and function of the supraspinatus muscle, which is crucial for shoulder abduction and stabilization. When the arm is positioned in the "empty can" position (thumb down), and resistance is applied, pain or weakness suggests that there may be an issue with the supraspinatus, such as a tendonitis or tear.

The interpretation of this test focuses on the muscle's ability to withstand resistance in a specific position that emphasizes its function. Thus, the presence of pain or weakness directly correlates with dysfunction in the supraspinatus, making it a reliable indicator of a positive test result. This is particularly relevant in clinical settings where shoulder injuries are suspected, helping practitioners to narrow down the differential diagnosis related to shoulder pathology.